Surface Heating Unit Having Selective Concentric Electric Sheathed Heating Elements

Abstract

A surface heating unit having circular electric sheathed heating elements. The electric heating elements selectively supporting round-bottom, Chinese wok-type cooking vessels as well as cnventional flat-bottom vessels on an electric range top or other such installation.

Description

This invention relates to a sheathed, rigid, electric heating element combination primarily of the range top variety.

The primary purpose of this invention is to render possible the use of a cooking vessel of the type commonly known as Chinese wok on an electric stove or other such installation, while maintaining the same range top surface area available to conventional flat-bottom vessels.

The Chinese wok type vessel is a metallic cooking vessel, variable in size, with rounded bottom, so that it is in the shape of a hollow sphere, but never so much as a hemisphere, and the cooking is normally done in the bottom 1 or 2 inches of this vessel. Heretofore, cooking in such a vessel has been limited to gas flame-type stoves because the typical flat-surfaced heating element is not adapted to use with the wok-type vessel and the existing spring, resilient coil and other models are of too complicated construction, difficult to clean, or not vertically extendable enough to allow for the accommodation of so deep and curved a surface as that presented by the wok-type vessel in the normal range top configuration.

It is hence an object of this invention to provide an electric, range-top heating element in which a round-bottom, wok-type vessel can be heated and cradled in upright position without rolling over.

Another object of this invention is to provide an electric, heating element of the character described, which will accommodate either conventional, flat-bottom vessels or round-bottom, wok-type vessels.

Still another object of this invention is to provide a strong and durable, sheathed, electric heating element of the character described, which shall be relatively simple, inexpensive to manufacture, easy to clean and manipulate, and which shall yet be practical and efficient to a high degree in use.

Other objects of this invention will in part be obvious and in part hereinafter pointed out.

The invention accordingly consists in the features of construction, combination of coils, and arrangement of parts which will be exemplified in the construction hereinafter described, and of which the scope of invention will be indicated in the following claims.

FIG. 1 is a top plan view of the electric range-top, double, sheathed, heating element embodying the invention and composed of two separate and independent, concentric, sheathed, heating coils;

FIG. 2 is a cross-sectional view taken on line 2--2 of FIG. 1;

FIG. 3 is a view similar to FIG. 2, but showing the interior heating element and its support removed to enable the outer heating element to heat and cradle the wok-type vessel.

FIG. 4 is a perspective view of a modified electric cooking stove heating element which will accommodate either flat or curved bottomed cooking vessels;

FIG. 5 is a cross-sectional view taken on line 5--5 of FIG. 4;

FIG. 6 is a perspective view of another modified form of the invention; and

FIG. 7 is a cross-sectional view taken in line 7--7 of FIG. 6.

Referring in detail to FIGS. 1, 2 and 3 of the drawings, numeral 10 designates an electric cooking stove body, having a top wall 11, formed with a round hole 12.

Fitted into this hole 12 is a heat reflecting cup 13. Such cups are known for electric range tops. Said cup 13 has an upper, outwardly extending, annular flange 14 resting on top of the wall 11. Extending down from flange 14 is a cylindrical wall 15, from which there extends radially inwardly, a flat annular horizontal wall or shoulder 16. Extending down from wall 16 is a rounded wall 17, having a central bottom hole 18 and receiving feet 41 of tripod support 40. Said cup 13 has an opening 19 at one side for the purpose hereinafter appearing.

Fixed to the stove body 10 in any suitable manner (not shown) is a box 20, open at its inner side and located opposite opening 19 in the cup 13.

Extending into box 20 are a pair of electric conductors 22, formed with resilient snap terminal prongs 23, and another such pair of conductors 24, provided with similar resilient snap terminal prongs 25. Conductors 22 and 24 connect to sources of electric energy. Such terminal conductors are known for electric ranges. On shoulder 16 are three, equiangularly-spaced, radial, vertical ribs 16a, fixed thereto in any suitable manner. The function of these ribs is the support of the exterior heating element 30.

Element 30, resting on said ribs 16a, has an annular split portion 30a, from the ends of which end portions 31 and 32 extend downwardly. From portions 31 and 32 horizontal end portions 31a and 32a extend radially outwardly and pass out of the cup 13 through opening 19 and into the box 20 through the open end thereof. Said split annular or circular portion 30a has a larger, flat, horizontal surface 30b and a broad, inner, slightly curved surface 30c to conform to the surface of a wok-type, cooking vessel W. This surface form is distinct from that of ordinary range-top, heating elements in that it presents a broad heating surface laterally on the inside as well as at the upper surface, so that when the inner element is removed the wok-type vessel may be heated laterally, or when it is in place, an ordinary, flat-bottom vessel may be heated on its upper surface.

End portions 31a and 32a terminate in terminal knobs rotatably received in the snap prongs 25. The heating element 30 is thus energized through the conductors 24. Proper switch means to turn the element on and off is provided in the well known manner. Element 30 is removable, but for cleaning pruposes only.

Disposed in the cup and resting on the bottom curved portion 17 of said cup is the tripod support 40 having three legs 41, fitting in cup 13, and radiating portions 42 and a top cap 43. The radiating portions of the support 40 are in a plane just below the plane of the underside of sheathed element 30. Either fixed to or resting on said radiating portions 42 of the support 40 is the inner, sheathed, heating element 45, which has a portion 45a, spiral in shape, as shown in FIG. 1, lying in the plane of element 30. Said spiral portion 45a has only a flat upper surface 45b in the plane of flat surface 30b of split annular portion 30a for the heating of flat-bottom vessels.

At the inner end of element 45 is a downwardly extending portion 46 from which a horizontal portion 47 extends radially outwardly, passing through opening 19 in cup 13 and into box 20 and terminating in a knob terminal 46a, rotatably received in one of the snap terminals 23.

Extending from the outer end of the spiral portion of element 45 is a downwardly extending portion 48 from which a horizontal portion 49 extends outwardly in parallel relation to portion 47, passing out through opening 19 in cup 13 and into box 20 and terminating in a knob terminal 47a, swivelly snap-fitted into the other snap terminal 23, in the well-known manner.

It will now be seen that when both elements 30 and 45 are used, flat-bottom cooking vessles can be placed on the said elements. Such vessels rest on surfaces 30b and 45b. If it is desired to cook with a round-bottom, Chinese wok-type cooking vessel, the inner element 45 may be swung up to the dot-dash position of FIG. 2 and then pulled out and removed along with its tripod support 40.

Then a Chinese wok-type cooking vessel W can be placed on the stove and it will contact, cradle and center on, and be heated by the broad inner surface 30c of the round or circular portion 30a of the larger electric element 30, to permit cooking and to prevent the rounded vessel from rolling over.

Referring now to FIGS. 4 and 5, there is shown a heating element 60 illustrating a modified form of the invention. In this modification, the single heating element 60 has means for supporting both a flat bottom walled cooking vessel as well as a Chinese type wok cooking vessel with a rounded bottom. Element 60 has a top circular portion 61 which is in a horizontal plane but somewhat less than 360.degree. in angular extent. At one end of said circular portion 60 is an outwardly extending portion 61a from which there extends downwardly a portion 62 from which a horizontal portion 63 extends radially outwardly. Extending from the other end of circular portion 61 is a spiral portion 65 formed in a part spherical surface and decreasing in radius downwardly to a point 66 from which a radial portion 67 extends outwardly. Extending downwardly from portion 67 is a portion 68 parallel to portion 62 (but shorter than said portion 62). Extending outwardly from portion 68 is a portion 69 parallel to and at same horizontal level as portion 63. Said portions 63, 69 terminate in knobs 70 (like knobs 47a, of FIG. 2) to be received in snap terminals (like terminals 23 of FIG. 2).

Annular portion 61 has a top flat horizontal surface 61a and an inner curved surface 61b conforming to the outer surface of a wok type cooking vessel. Spiral element 65 has a top flat horizontal surface 65a and an inner curved surface 65b conforming to the contacting surface of a wok type cooking vessel W mounted on or contacting surface 61b.

A Chinese wok type cooking vessel will cradle and be supported in upright position in portion 65 of the element 60.

Thus element 60 will support flat bottomed as well as round bottom cooking vessels.

In FIGS. 6 and 7 there is shown elements 80 and 81 which are coaxial. Element 80 is at a higher level than element 81 and has a somewhat less than circular horizontal portion 82 from the ends of which portion 83 extend downward. Extending from portion 83 are parallel horizontal portions 84 terminating in knobs 85.

Element portion 82 has a top flat horizontal surface 81a and an inner curved surface 82b.

The lower element 81 has a somewhat less than circular portion 86 in a horizontal plane and of a diameter less than the diameter of circular portion 82 of element 80. Extending down from the ends of portion 86 are vertical parallel portions 87 from which parallel horizontal portions 88 project outwardly and terminate in knobs 89.

Portion 86 of element 81 has a top flat horizontal surface 86a and an inner curved surface 86b which matches curved surface 82b so that a wok type cooking vessel W will cradle in and contact surfaces 82b, 86b.

The knobs 85 and 89 are received in snap terminals (not shown but like terminals 23 of conductors receiving electric energy).

A cooking vessel with a flat bottom can rest on top surface 81a of element 80. A Chinese type wok or any cooking vessel with a rounded bottom can be placed on both elements 80, 81 as illustrated in FIG. 7. The upper element 80 is like element 30 of FIGS. 1 and 2 and may be supported in a reflecting cup 13 as shown in FIG. 2. The lower element 81 may be supported in a reflecting cup 13 in any suitable manner. It may rest on the inside of the cup 13 or on a support placed in the cup.

The heating element 81 may be removed if desired to cook with heating element 80 alone. The heating element 80 may be removed to cook with element 81 alone.

It will thus be seen that there is provided an article in which the several objects of this invention are achieved, and which is well adapted to meet the conditions of practical use.

As possible embodiments might be made of the above invention, and as various changes might be made in the embodiments above set forth, it is to be understood that all matter herein set forth or shown in the accompanying drawings, is to be interpreted as illustrative only.

Claims

We claim:

1. A combination comprising a top wall having a hole, a reflecting cup mounted on said wall and projecting down into said hole and having a rounded wall, electric heating element means provided with end electric terminals and comprising means to selectively support and heat either a flat bottomed cooking vessel or a round bottomed cooking vessel, said means comprising a pair of sheathed, tubular electrical coaxial inner and outer heating element portions, and means on said cup to support said element portions, said element portions being so arranged as to selectively support either a flat bottomed or a round bottomed pot.

2. The combination of claim 1, said portions comprising parts of a single heating element.

3. The combination of claim 2, one of said portions having a top, flat, horizontal surface and an inner curved surface, and said other portions having an inner curved surface.

4. The combination of claim 1, said portions comprising a pair of separate and separable heating elements, said heating elements each having ends and electric terminals at said ends thereof.

5. The combination of claim 4, one heating element having a top, flat, horizontal surface and an inner curved surface and said other heating element having an inner curved surface.

6. The combination of claim 1, said heating element means having a top flat horizontal surface and an inner curved surface.

7. The combination of claim 1, a reflecting cup adapted to be fitted into a hole in the top wall of a stove body, said reflecting cup having means to engage the stove body to support said cup on said body, means on said cup to support the outer electric heating element portion, and means removably mounted in the cup to support said inner electric heating element.

8. A combination comprising a first outer electric sheathed, tubular heating element and a second inner separate electric sheathed, tubular heating element coaxial with and separable from said first heating element and of less diameter than said first heating element said heating elements each having ends and terminals at said ends, a top wall having a hole, a reflecting cup in said hole and supports in said cup for said heating elements.

9. The combination of claim 8, said heating elements being located in the same plane to support a flat bottomed cooking vessel placed on both said elements, said inner element being removable to allow a round bottomed cooking vessel to be supported on said outer element.

10. The combination of claim 9, said first heating element being circular, said second heating element being spiral in shape.

11. The combination of claim 8, said heating elements being located in different horizontal planes.

12. The combination of claim 8, said first heating element being at a higher level than said second heating element.

13. The combination of claim 12, said first and second heating elements being circular.

14. The combination of claim 12, said first heating element being of a larger diameter than said second heating element.

15. The combination of claim 8, said first heating element having a top, flat, horizontal surface and an inner curved surface, said second heating element having a flat, top, horizontal surface.

16. A combination comprising, an electric sheathed tubular heating element including a split circular element portion, terminals at the ends of said element, whereby a flat bottomed cooking vessel can be placed on top of said split circular portion and a curved bottom cooking vessel can be cradled in said split circular element portion to project therebelow, a top wall having a hole, a reflecting cup on said wall and in said hole and means on said cup to support said heating element, said heating element having a flat top surface and an inner curved surface.